Indian Overseas Bank — maintenance charges

I have been charged an amount of almost 700 rs for not maintaining minimum balance, perambur branch people don't inform customers about minimum balance as well as charges applied, when i asked them about so much charges they said it's computerized, i was not informed about so many charges as well as minimum balance, around 118 rs was deducted from my account for every month and over all at a shot 669 rs was deducted.